Hi Michael,

Your proposal won’t save any energy because it does nothing to decrease the
budget available to mine a block (being the block reward).

Even if it were technically possible to find a way for nodes to somehow
reach consensus on a hash that gets generated after 9 minutes, all it
achieves is that miners will be expending the entire budget given to them
in the form of the block reward within a single minute on average.

Also please realize that the energy expenditure of Bitcoin is a fundamental
part of its design. An attacker has no other option than to expend as much
as half of all the miners together do in order for a sustained 51% attack
to be successful, making such attack uneconomical.

Zac

On Sat, 15 May 2021 at 23:57, Michael Fuhrmann via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

> Hello,
>
> Bitcoin should create blocks every 10 minutes in average. So why do
> miners need to mine the 9 minutes after the last block was found? It's
> not necessary.
>
> Problem: How to prevent "pre-mining" in the 9 minutes time window?
>
> Possible ideas for discussion:
>
> - (maybe most difficult) global network timer sending a salted hash time
> code after 9 minutes. this enables validation by nodes.
>
> - (easy attempt) mining jobs before 9 minutes have a 10 (or 100 or just
> high enough) times higher difficulty. so everyone can mine any time but
> before to 9 minutes are up there will be a too high downside. It is more
> efficient to wait then paying high bills. The bitcoin will get a "puls".
>
>
> I dont think I see all problems behind these ideas but if there is a
> working solution to do so then the energy fud will find it's end. Saving
> energy without loosing rosbustness.
>
>
>
> :)
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